WO07/028654 describes a number of pyridine derivatives or pharmaceutical acceptable salts thereof as antagonists of the NK1 and NK3 receptors and thus may be of use in the treatment of psychotic disorders. In particular, the compound 2-[3,5-Bis(trifluoromethyl)phenyl]-N-{4-(4-fluoro-2-methyl phenyl)-6-[(7S,9aS)-7-(hydroxymethyl)hexahydropyrazino[2,1-c][1,4]oxazin-8(1H)-yl]-3-pyridinyl}-N,2-dimethylpropanamide or pharmaceutical acceptable salts thereof are described in WO07/028654.
Hydrochloride salt of 2-[3,5-Bis(trifluoromethyl)phenyl]-N-{4-(4-fluoro-2-methylphenyl)-6-[(7S,9aS)-7-(hydroxymethyl)hexahydropyrazino[2,1-c][1,4]oxazin-8(1H)-yl]-3-pyridinyl}-N,2-dimethylpropanamide is also described in WO07/028654.
The structure of 2-[3,5-Bis(trifluoromethyl)phenyl]-N-{4-(4-fluoro-2-methylphenyl)-6-[(7S,9aS)-7-(hydroxymethyl)hexahydropyrazino[2,1-c][1,4]oxazin-8(1H)-yl]-3-pyridinyl}-N,2-dimethylpropanamide is shown in formula (I) below.

Pharmaceutical acceptable salts of the compound of formula (I) include acid addition salts formed with inorganic acids such as hydrochloric, hydrobromic, hydroiodic, phosphoric, metaphosphoric, nitric and sulfuric acids, and with organic acids, such as tartaric, acetic, trifluoroacetic, citric, malic, lactic, fumaric, benzoic, formic, propionic, glycolic, gluconic, maleic, succinic, camphorsulfuric, isothionic, mucic, gentisic, isonicotinic, saccharic, glucuronic, furoic, glutamic, ascorbic, anthranilic, salicylic, phenylacetic, mandelic, embonic (pamoic), methanesulfonic, ethanesulfonic, pantothenic, stearic, sulfinilic, alginic, galacturonic and arylsulfonic, for example benzenesulfonic and 4-methyl benzenesulfonic acids.
The compound of formula (I) or its hydrochloride are obtained, according to the procedure described in WO07/028654, as partially amorphous or wholly amorphous solids and it is hygroscopic. Amorphous solids and particularly hygroscopic solids are difficult to handle under pharmaceutical processing conditions typically because of low bulky densities and unsatisfactory flow properties.
Accordingly, a need exists for crystalline forms of the compound of formula (I) with superior physiochemical properties that may be used advantageously in pharmaceutical processing and pharmaceutical compositions.